Safety device for percussion fuse

ABSTRACT

A safety device is provided which can slide in axial direction inside a seating of a fuse, wherein it can be locked in an extreme position toward the back of the fuse before missile discharge. The device has a primary part which is initially locked in a position to the front of the fuse and a second part which can slide relative to the first one. An interlock is provided between the primary and second parts and provision is made for disengaging these parts when the primary part is frontward in the fuse. A third part is provided which is capable of sliding relative to the second part. An interlock couples the second and third parts but provides for disengaging them after the second part has been disengaged from the primary part. A percussion device associated with the third part effects the operation of the fuse during the frontward movement of the third part after disengagement thereof from the second part.

Daniel SAFETY DEVICE FOR PERCUSSION FUSE [75] Inventor: Andr Francis Albert Daniel,

Bourges, France [73] Assignee: Etat Francais, Paris, France [22] Filed: Feb. 1, 1971 [21] Appl. No.: 111,658

[30] Foreign Application Priority Data Apr. 22, 1970 France 70.l4529 52 us. Cl, ..L 102/78 s [51] Int. Cl. F42c 15/04 [58] Field of Search l02/70-78 [56] References Cited UNITED STATES PATENTS 2,243.62l 5/l94l Denoix l02/70S 2,872,868 2/l959 Donahue, Jr. 102/78 3,557.70] l/l97l Arnell l02/76R Primary ns rfiemuelw-E951 V, Attorney, Agent, or Firm-Waters, Roditi, Schwartz &

Nissen 5 7] ABSTRACT locked in an extreme position toward the back of the fuse before missile discharge. The device has a primary part which is initially locked in a position to the front of the fuse and a second part which can slide relative to the first one. An interlock is provided between the primary and second parts and provision is made for disengaging these parts when the primary part is frontward in the fuse. A third part is provided which is capable of sliding relative to the second part. An interlock couples the second and third parts but provides for disengaging them after the second part has been disengaged from the primary part. A percussion device associated with the third part effects the operation of the fuse during the frontward movement of the third part after disengagement thereof from the sec- 0nd part.

7 Claims, 3 Drawing Figures June 4, 1974 E PATENTEBM 1914 3.814.018

SHEET 3 0F 3 FIG. 3

1 SAFETY DEVICE FOR PERCUSSION FUSE FIELD OF THE INVENTION This invention relates to safety devices for inertial percussion fuses.

BACKGROUND the other hand, the various actions produced during theoperations which must not in any case entail such arming.

Likewise, in an inertial fuse, the slow-down undergone by the missile along its flight-path must not cause percussion of the charge, whereas the slowing-down obtained on impact must cause such percussion.

' SUMMARY OF THE INVENTION The present invention allows the achieving of the aforegoing objects by preventing the priming of the explosive charge of a missile, whether rotating or not, even if the missile motion comprises a comparatively low-amplitude deceleration phase after take-off.

According to the invention, it is during this phase that the first portion of an arming drill operates, the second portion coming into operation when the deceleration has reached a very low value.

Another object of the invention is to produce a safety device for inertial fuses by the use of comparatively inexpensive and dependable mechanical means.

More precisely, in accordance with the invention, there is provided a fuse safety device that can slide in an axial or appreciably axial direction inside a seating in the said fuse, wherein the device can be locked in an end position toward the back of the fuse before the firing of the missile. This device comprises: a seating, 21 primary part slidable in said seating; a second part able to slide in relation to the primary part; means for allowing the same to interlock the said primary and second parts and to disengage when the primary part comes to the front of the fuse; means for enabling the locking of the primary part in the front position after the disengagement and return of the second part to the rear of the fuse; a third part sliding in relation to the second part; means for interlocking the said second and third parts and for disengaging them after the second part has been disengaged from the primary part; and a percussion device combined with the third part and bringing the fuse into operation when the frontward movement of the said third part takes place after disengagement with the second part.

Another object of theinvention is to provide a device, as described above, wherein the means for locking the first part in its front position and the means for disengaging the first and second parts come into effect through a'single means that can occupy two different positions, due to two series of recesses carried respectively by the second part and by the side wall of the seating of the device, and due also to hollows machined in the primary part.

As a feature of the invention, the said single means is made up of spheres of tough material and the recesses machined in the second part comprise a portion inclined to the axis frontward of the fuse to facilitate the clearing of the said spheres in the position of disengagement for the primary and second parts.

According to a further feature of the invention, the means for interlocking and the means for disengaging the second and third parts are achieved by a single means that can occupy two different positions because of recesses machined in the third part and hollows machined in the second part, the said disengagement being obtained by means of a spring.

According to still a further feature of the invention, the said single means is composed of spheres of tough material and the recesses machined in the third part comprise an inclined portion to facilitate the clearing of the said spheres in the position of disengagement for the second and third parts.

According to yet another feature, certain shiftings of the various parts can be effected by means other than inertial operation, for example, by means comprising countersprings, time-lag mechanisms or devices sensitive to the rotation of the missile.

To provide better understanding of the invention, a preferred but nonlimitative embodiment will be de scribed hereunder with reference to the attached drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a sectional view of a device according to the invention in its position of rest;

FIG. 2 is a corresponding sectional view of the same device in the position it assumes immediately after the missile take-off; and

FIG. 3 is a corresponding sectional view of the same device in the last phase of the arming sequence.

DETAILED DESCRIPTION In FIG. I, a primary part called the outside part 8 can be seen on the inside of a cylindrical seating 4. Part 8 is able to slide inside seating 4 and is furnished also with hollow or openings 7' each containing a small metal sphere 7 of a diameter greater than the thickness of part 8.

The outside part 8 can be locked (FIG. 1) at the back of the fuse by means of stop pins 5. It can also be locked at the front of the fuse (FIG. 3) when the balls 7 partially enter into recesses 6 provided in the wall of seating 4.

A second part 2, called the center bit, is in the form of a hollow cylinder and can slide relatively to part 8.

Part 2 comprises, on the one hand, some cam-shaped recesses 2T workingin conjuction with the balls 7 and, on the other hand, hollow or openings 9' each holding a metal ball 9'. Recesses 6 have a depth exceeding that of recesses 2' to permit clearance of spheres 7. Part 8 has a thickness exceeding the depth of recess 3' to permit clearance of spheres 9 when the part 8 clears the recess 3.

In front of center bit 2, a bolster accommodates a spring 1 which is further supported on the wall in front of seating 4. A third part 3, called the inside part, carries the percussion mechanism 12.

This part is equipped with the cam-shaped circular grooved recess 3' toward its rearmost end and can slide in the center bit 2. The circular recess working with the openings 9 of the center bit 2 and with balls 9 interlocks the two parts 2 and 3 during the first stage of the arming sequence.

The arming process is as follows:

First stage (H6. 1) at rest, the three parts 2,3 and 8 are locked in rearmost position;

Second stage (FIG. 2) missile take-off after clearing the pins 55 take-off deceleration, even though small compresses spring 1 and all of the three parts 2,3 and 8 are shifted as a unit frontward relative to seating 4;

Third stage when acceleration is sufficiently reduced, the spring 1 thrusts the center bit 3 backward, and this moves the balls 7 (due to the sloped or camshaped configuration of recesses 28) into the hollows 6, the effect whereof is to lock the outside part 8 to the seating 4, while the center and inside bits come to rest on a stop 10 located at the rearmost end of seating 4;

Fourth stage (H6. 3) during the slowing-down period, the inside part 3 is shifted forward displacing the balls 9 from groove 3 due to the sloped or cam-shaped configuration of the latter.

The percussion device is then in operating-position, to procure percussion on impact of the missile.

What is claimed is:

l. A safety device adapted to slide toward the front and back of a fuse inside a seating in said fuse and adapted for being locked in an extreme position toward the back of the said fuse before discharge of a missile including said fuse, said device comprising: a primary part slidable in said seating from the back to the front of the fuse, means to hold said primary part in said extreme position and controllable to release said primary part to slide to the front, a second part adapted for slding relative to the primary part; first interlocking means for interlocking the said primary and second parts and enabling the same to disengage when the primary part moves toward the front of the fuse; means enabling the locking of the primary part in the front position after the disengagement and return of the second part to the rear of the fuse, a third part adapted for sliding relative to the second part; second interlocking means for interlocking the said second and third parts and enabling the same to disengage after the second part has been disengaged from the primary part; and a percussion device operatively associated with the third part and effecting the operation of the fuse during frontward movement of the said third part after disengagement thereof from the second part, said first and second interlocking means causing the primary, second and third parts to move jointly to the front before the disengagement of the second and third parts.

2. A device according to claim 1 wherein the means for locking the primary part in the front position and the first interlocking means for interlocking the primary and second parts cooperatively include a single means adapted to occupy two distinct positions, for cooperation with two recesses respectively provided in said second part and said seating, said single means being carried in an opening provided in the primary part.

3. A device as in claim 2 wherein the said single means includes at least one sphere of tough material and wherein the recess provided in the second part includes an inclined portion to facilitate clearance of the said sphere to the recess in the seating for disengagement of the primary and second parts.

4. A device as in claim 1 wherein the second interlocking means for interlocking the second and third parts cooperatively include a single means adapted to occupy two distinct positions for selective cooperation with a recess provided in the third part, said single means being carried in an opening provided in the second part, said device further including a spring for urging the second part toward the rear of the fuse.

5. A device as in claim 4 wherein the said single means includes at least one sphere and wherein the recess provided in the third part comprises an inclined portion to facilitate the clearance of the said sphere into a position for disengagement of the second and third parts.

6. A device as claimed in claim 3 wherein the recess in the seating has a depth at least equal to the depth of the recess in the second part to permit clearance of said sphere from the recess in the second part.

7. A device as claimed in claim 5 wherein the primary part has a thickness at least equal to the depth of the recess in the third part to permit clearance of said sphere from the recess in the third part when the primary part is displaced from the latter said recess. 

1. A safety device adapted to slide toward the front and back of a fuse inside a seating in said fuse and adapted for being locked in an extreme position toward the back of the said fuse before discharge of a missile including said fuse, said device comprising: a primary part slidable in said seating from the back to the front of the fuse, means to hold said primary part in said extreme position and controllable to release said primary part to slide to the front, a second part adapted for slding relative to the primary part; first interlocking means for interlocking the said primary and second parts and enabling the same to disengage when the primary part moves toward the front of the fuse; means enabling the locking of the primary part in the front position after the disengagement and return of the second part to the rear of the fuse, a third part adapted for sliding relative to the second part; second interlocking means for interlocking the said second and third parts and enabling the same to disengage after the second part has been disengaged from the primary part; and a percussion device operatively associated with the third part and effecting the operation of the fuse during frontward movement of the said third part after disengagement thereof from the second part, said first and second interlocking means causing the primary, second and third parts to move jointly to the front before the disengagement of the second and third parts.
 2. A device according to claim 1 wherein the means for locking the primary part in the front position and the first interlocking means for interlocking the primary and second parts cooperatively include a single means adapted to occupy two distinct positions, for cooperation with two recesses respectively provided in said second part and said seating, said single means being carried in an opening provided in the primary part.
 3. A device as in claim 2 wherein the said single means includes at least one sphere of tough material and wherein the recess provided in the second part includes an inclined portion to facilitate clearance of the said sphere to the recess in the seating for disengagement of the primary and second parts.
 4. A device as in claim 1 wherein the second interlocking means for interlocking the second and third parts cooperatively include a single means adapted to occupy two distinct positions for selective cooperation with a recess provided in the third part, said single means being carried in an opening provided in the second part, said device further including a spring for urging the second part toward the rear of the fuse.
 5. A device as in claim 4 wherein the said single means includes at least one sphere and wherein the recess provided in the third part comprises an inclined portion to facilitate the clearance of the said sphere into a position for disengagement of the second and third parts.
 6. A device as claimed in claim 3 wherein the recess in the seating has a depth at least equal to the depth of the recess in the second part to permit cLearance of said sphere from the recess in the second part.
 7. A device as claimed in claim 5 wherein the primary part has a thickness at least equal to the depth of the recess in the third part to permit clearance of said sphere from the recess in the third part when the primary part is displaced from the latter said recess. 